This is a demonstration study aimed at developing and evaluating a program for reducing cigarette smoking in the population of pregnant women who are members of Northwest Kaiser Permanente (NWKP). The project builds on a firm foundation of our previous work in outpatient, low-intensity smoking cessation and our ongoing trial addressing smoking behavior in mothers through pediatric offices, and on a significant body of literature supporting physician advice and other smoking cessation strategies in ambulatory populations, including pregnant women. Pregnant women who smoke constitute a high-risk group, given the risks for both mother and the passive smoke exposure risks for fetuses and newborns. The study will develop, implement, and evaluate a region-wide intervention initially aimed at pregnant mothers and continuing through delivery and the first six months of pediatric well-baby care. The program is based on the philosophy that health promotion, including smoking cessation should become a routine aspect of maternal prenatal and postnatal care, and that cost-effectiveness of mechanisms for medical care systems to deliver health promotion must be assessed. Smoking will be routinely assessed and recorded at each visit. Physicians, nurses, and nurse practitioners will deliver brief, stage-appropriate messages and materials at most visits. A tailor-made video will be shown during both prenatal and pediatric (postnatal) phases, letters to fathers, and mailed newsletters, partly aimed at husbands, will also be employed. Intervention efficacy will be evaluated using a quasi-experimental design. The comparison group will be smoking, pregnant women assessed prior to implementing intervention at the same clinics. Changes in smoking rates in the population of women at one year after delivery will be the primary end point. Secondary aims include evaluating possible changes in husband smoking; analyzing predictors of cessation among women; evaluating provider perceptions of the feasibility, efficacy, and value of the intervention; and evaluating maintenance of the intervention after project completion.